Last time when I checked it, it didn't cause this particular issue either. I think it might've just replaced the default choice of mounting the image with something else.

No, that's the first thing I checked. It opens with Explorer and has all the proper context menu options to mount or burn. With all you get the busy cursor for about 10 minutes before it times out and reports could not mount. Could be something unique with other installed software I have, but the cause was iTunes 11.

I wanted to keep it given the major price differences but I use ISOs regularly, so I'll have to install on demand for now.

Obviously any software that can handle images can override the Win 8 mounting when you double click an image, 7-Zip can do it for example if you tell it to associate with *.iso.

All you need to do to re-associate is to right click an iso and select to open them with Windows Explorer and tick the checkbox so it does so in the future.

As I stated in response to someone else, it is NOT an association problem. They are associated and try to mount with Explorer. With iTunes 11 installed, Explorer times out trying to mount them. On my system anyway.

I don't buy a whole lot, but if I do an what I purchase continues to be 50% cheaper on iTunes than on Xbox Music store, I will go with Daemon Tools.

I also have the Metro App hyperlink fail issue. I know what that is as well, Microangelo OnDisplay corrupts the HKLU CLSID key. Removing all entries doesn't work. Key must be deleted. I'm living without hyperlinks because I must have all my custom icons all over. Others have it, some have Microangelo, some do not. Legacy app oddities.